Our Family's Nature Blog

Almost two weeks ago we solved the mystery of what warblers were eating in the streets of south Oak Park: Beetle larvae!

Well, the beetle larvae are not longer tumbling from our elm trees, but the warblers and thrushes and Indigo Buntings keep coming, along with tanagers and orioles and more! So, to find out what the birds are eating now, I grabbed a white plastic box lid, held it under some low elm branches, and started shaking:

Just in case someone out there can identify what type of moths or butterflies these become, here are some closer views:

I can’t identify the caterpillars, but I do know they taste good to birds. During the past week, we’ve seen 23 kinds of warblers feeding in and under our elm trees:

Golden-winged Warbler

Tennessee Warbler

Orange-crowned Warbler

Nashville Warbler

Northern Parula

Yellow Warbler

Chestnut-sided Warbler

Magnolia Warbler

Cape May Warbler

Yellow-rumped Warbler

Black-throated Green Warbler

Blackburnian Warbler

Palm Warbler

Bay-breasted Warbler

Blackpoll Warbler

Black-and-white Warbler

American Redstart

Ovenbird

Northern Waterthrush

Mourning Warbler

Hooded Warbler

Wilson’s Warbler

Canada Warbler

Feeding along with the warblers we’ve seen:

Yellow-throated Vireo, Warbling Vireo, and Red-eyed Vireo

Veery, Gray-cheeked Thrush, and Swainson’s Thrush

Gray Catbird

Summer Tanager and Scarlet Tanager

Rose-breasted Grosbeak

Indigo Bunting

and Baltimore Oriole

These birds are all spring migrants. The Catbird is the only one who’s likely to stay and nest in our neighborhood. The caterpillars in our elm trees have helped them survive and refuel before the next night with southerly winds to speed them on their journey north.

Did I mention that last week we found thousands of tiny caterpillar poops on our cars each morning? The polite term for caterpillar poop is frass. This morning our cars were almost frass-free, although there was lots of bird poop on our windshields.

We’ll finally get some southerly winds later this week, so we expect most migrant birds to continue north. In their wake we expect our elms to enjoy an almost caterpillar-free summer.

Now if we could just find a biological control for the bark beetles that spread Dutch Elm Disease….

Every spring there are a few days in late April and early May when we see warblers in the streets, feeding on something. Two years ago it happened in late April, as seen in these photos of Yellow-rumped Warblers on our south Oak Park block:

Well, it’s been happening again the past few days. It’s like a block party for the birds, and it got me wondering–what’s for breakfast, lunch, and dinner? What tasty things are the warblers feeding on?

My best guess was that there was some sort of insect feeding on the opening leaves of the American Elms that tower over many sections of our block. Every spring there are also warblers feeding on something in the treetops, and every year there are tiny holes chewed in the leaves:

So, I was thinking that maybe whatever was feeding on the leaves somehow fell to the ground, where sharp-eyed warblers could spot them on the asphalt and continue their meals.

To test my hypothesis, I placed a white plastic lid where it could catch whatever was falling. I left it there from late afternoon yesterday until early this morning:

Then, this morning, I brought the lid inside to see what I could find. It was covered with tiny, pale yellow grub-like insect larvae!

So, one question answered: That’s what’s falling from the trees, and probably what the warblers are eating. But many questions remain:

What are these things? Hatchling caterpillars, or some other kind of insect?

Why are so many falling from the trees? Shouldn’t they be better adapted to hang onto the leaves? Or do they “jump” whenever a bird is picking at their leaf?

Once they hit the ground, they are still alive–you can see them moving. Can they somehow continue to live on the ground, perhaps feeding on fallen elm leaves and elm seeds? If so, when they are larger and stronger, would they climb back up into the trees?

So, I guess our next challenge is to try to raise a bunch of the larvae until they are large enough to identify. And once they are bigger we can put some of them at the base of an elm tree and see what happens.

I’ll let you know what happens!

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A few hours I posted this, a Facebook friend and garden designer made this comment (Thanks, René!):

“I’m no entomologist, but after some research, my best guess is Elm Leaf Beetle. These guys feed on elms and drop to the ground in large numbers as little yellow guys to pupate. Sounds like the yellow-rumped Warblers are doing a good job of natural pest control.”

For more than 10 years our family has been collecting Buckeyes from a tree near our home. Why? Well, Buckeyes are just great things to have, and to hold, and to rub with your thumb and carry around in your pocket! So, I got really excited when I found the first of the new crop laying on the street:

The Buckeye nuts are inside a leathery husk. Squirrels had started chewing through the husk, but given up. The husks are an inch or two in diameter.

I took them home and cut into the husk, hoping I could peel it off to find the shiny brown nut inside. No such luck! The husk was really thick, and when I cut all the way through, I could see the nuts were nowhere close to ripe:

I cut a Buckeye in half. The white thing inside would have become a nut if the squirrels and I had waited.

So, I guess I should have waited, and the squirrels must have reached the same conclusion once they tasted what was inside the husk. But it doesn’t seem fair, because I have been waiting on this tree for more than two months! I waited while the Buckeye flowers bloomed in mid May:

The Buckeye flowers looked like this way back on May 19, 2009.

When you look closely, Buckeye flowers are very beautiful, but they aren't much fun to play with.

I waited as the nuts began to grow later in May:

The Buckeye nuts looked like this after the flowers had faded away, on May 27, 2009.

I waited as the nuts grew all through June:

By June 18, only a few Buckeye nuts survived on this old flower stalk.

And I waited through the first weeks of July:

The growing Buckeyes looked like this on July 2, 2009.

And now, as the Buckeyes finally are approaching ripeness, we are preparing to leave on vacation! So, just to remind me of what I was missing, I cracked open an old Buckeye that had sat on a shelf since last summer:

This Buckeye sat, unopened, since last summer, until I cracked it open with a pair of pliers. Don't you want to pick up a Buckeye and rub it with your fingers (or throw it at your brother)?

I guess the squirrels will have this year’s Buckeye crop all to themselves. Unless, of course, you want to collect a few Buckeyes of your own. (This tree is in the northeast corner of Rehm Park in south Oak Park — but leave a few for the squirrels!)

This morning, while walking past Eastgate Cafe on my way to Columbus Park, I noticed some strange green things on one of the outdoor tables:

These strange green things had me stumped until I checked the Oak Park Tree Inventory.

I looked up into the tree they seemed to have fallen from, and I saw heart-shaped leaves with lots of teeth. Some teeth looked bigger than others:

The leaves were heard-shaped and had lots of teeth.

I was stumped! I had walked past this tree dozens of times and assumed it was something familiar, like maybe a kind of basswood. Obviously I had not been paying close enough attention!

Fortunately, the Village of Oak Park has published an inventory of trees planted along Village streets (2009 version available here as a large PDF file). I couldn’t find the Eastgate Cafe’s exact address in the Inventory, but I did come across an unfamiliar tree name–Turkish Filbert–that was found at other places along Harrison Street. So I googled around until I found some photos of Turkish Filbert fruits. Some of the photos looked kind of similar to what I found, and some looked like exact matches, like the photos found here and here.

Those photos came from an Oregon State University web page (here), which also listed several other species in the same genus (Colylus). Some of those had similar fruits, so I can’t say for certain that the Eastgate Cafe tree is Corylus colurna, the Turkish Filbert. However, it does seem to be of that genus. (Another name for this species is Turkish Hazel, but there are other kinds of bushes and trees called Hazels, so I’ll stick with the common name Filbert for now.)

You may recognize “filbert” as a kind of nut, also known as the “hazelnut,” and Turkish Filbert trees really do produce nuts that people can eat. However, Wikipedia says that Turkish Filbert nuts are too small and their shells are too thick for them to have much commercial value. (Other Corylus species, like Common Hazel, probably produced the nuts you’ve eaten.) Regardless, I’m going to visit this tree throughout the summer, hoping to find some ripe nuts that I can eat!

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Here are some additional web sites with information about the Turkish Filbert:

Colorado Trees: Web page with some basic information and small photos of Turkish Filbert trees.

Late last week I returned to Columbus Park to check on the families of Canada Geese and Wood Ducks. The five-week-old Canada Goose goslings were bigger than ever and starting to replace their downy coverings with some adult-like feathers:

This five-week-old Canada Goose is starting to look like its parents.

The goslings are growing fast because they almost never stop eating. Even as they rest, they continue to nibble on green grass at the edge of the lagoon:

The young Canada Geese rarely stop feeding on grass. One parent kept an eye on me as the other parent chased off another goose.

Unfortunately, I saw only four young geese that day. Sometime during the previous week a gosling was lost, perhaps to a predator like a dog or raccoon.

Dickcissels are small birds usually found in tallgrass prairies and unplowed farm fields. (As my friend Jane reminded me, “The character Laura in the book Little House on the Prairie watches Dickcissels flit in the tallgrass.”)

So this morning I was quite surprised to find one feeding in the brushy corner of our pocket-sized backyard in south Oak Park, Illinois! With their yellow-and-black breasts and stripy brown backs, Dickcissils look like miniature Meadowlarks:

The back-and-yellow breast, yellow-and-white eye stripe, and gray on the side of the head and neck identify this bird as a male Dickcissel.

However, our Sibley Guide groups Dickcissels with the tanagers, grosbeaks, and cardinals. Sibley also says that Dickcissels sometimes hang with House Sparrows, as this one was today. In fact, when they turn away, Dickcissel backs look a lot like House Sparrow backs:

The Dickcissel's back reminds me of a House Sparrow's back. However, the yellow on the eye stripe and the gray coloring on its half-turned neck give it away.

I guess it pays to look at every bird that visits your yard — you never know what will show up! It also pays to have a brush pile in your yard, however small. (Ethan repaired our brush pile earlier this spring.)

And wouldn’t it be cool if this male Dickcissel found his way to the meadow habitats in Columbus Park, less than a mile east of our yard?

Note added 2 p.m. the same day:

Jill Anderson, who monitors Miller Meadow for eBird, just posted a report on IBET. She said she stopped by Miller Meadow today and saw a male Dickcissel — the first one she’s seen there this year. She also confirmed that Dickcissels have nested there the past few years.

Note added a week later: On Saturday, June 6, we made our first to Midewin National Tallgrass Prairie, south of Joliet, Illinois. The place was packed with singing Dickcissels, especially near the Explosives Road Trailhead! (See this map. Midewin used to be part of the Joliet Army Ammunition Plant.)

We hope our backyard Dickcissel found a place like Midewin to spend the summer.

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To learn more about Dickcissels, please visit these websites:

All About Birds: For a basic description of this species, with photos and song recordings, go here.

Our neighborhood Tulip Tree is finally blooming! Lots of other trees flower first and then open their leaves, but Tulip Trees do the opposite. So, here’s a side view of the flower, which reminds me of a subtly colored garden tulip (if there is such a thing):

Our neighborhood Tulip Tree is finally flowering!

Now, let’s peek inside a flower. Because Tulip Trees are a kind of magnolia, there are lots of pollen-producing parts surrounding a cone-like mass of seed-producing parts. They say this is what some of the first flowers looked like, back during dinosaur times:

The Tulip Tree flower has lots of male parts surrounding a cone-shaped mass of female parts.

The next photo shows an unopened bud below a flower:

Some of the buds are not yet open -- that means you have a few more days if you want to see this Tulip Tree in bloom.

Oak Parkers and other who want to see Tulip Tree flowers can find this tree on the south side of Rehm Park, where Scoville deadends into the park. It’s a young tree, so some flowers are at eye level for adults. There are other Tulip Trees in town, but they’re so tall that you need binoculars to appreciate the flowers.

We’ve been following this tree since early spring. In case you missed those posts, here’s what a Tulip Tree twig looked like on April 29, when the leaf buds had just opened:

On April 29, the Tulip Tree buds had opened, revealing expanding leaves around the remains of last year's fruits.

Also on April 29, the flower buds were just beginning to form:

In late April the Tulip Tree's almond-shaped flower buds were rather small.

Back on April 8th, the leaf buds were opening below the remains of last year’s seed pods:

On April 8th, the Tulip Tree's duckbill-shaped leaf buds were just beginning to open.

If you want to see what happens once the flowers fade away and seeds begin to form, go here.

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Can you tell I like Tulip Trees? They remind me of my younger days, when I first explored the woodlands of southern Ohio and Indiana. I saw huge Tulip Trees in some of the old growth forests. I also love the link Tulip Trees provide to Early Cretaceous flowers (that’s the later part of dinosaur times). So, I’m glad that the Parks Department and Village Forester have planted at least a few Tulip Trees in our parks and along our streets.

This post is our contribution to this month’s Festival of the Trees. This blog carnival includes several other Tulip Tree posts, plus posts on other tree flowers, tree fruits, knots and gnarls, and more. Go here to read the festival entries.